23 Flashcards
(25 cards)
how is insulin synthesized?
synthesized as a pro-hormone or pre-cursor (proinsulin) that undergoes proteolytic cleavage to form insulin and C-peptide
why do C-peptide measurements provide a better index of how much insulin is being produced by the pancreas?
since insulin undergoes significant hepatic and renal extraction, plasma insulin levels may not accurately reflect insulin production
a patient who’s pancreas does not make any insulin (type 1 DM) has a ___ level of insulin and C-peptide
low
a patient with type 2 SM has ____ levels of insulin and C-peptide
can have a normal or high level
insulin preparations vary primarily on their:
onset, peak, and duration of effect
rapid, short, intermediate, long-acting
insulin is generally administered by:
subcutaneous injection
what does insulin act on and regulate?
acts via specific membrane-bound receptors on target tissues to regulate metabolism of carbohydrate, protein, and fats
target organs for insulin include:
the liver, skeletal muscle, and adipose tissue
within the liver, what does insulin stimulate?
hepatic glycogen synthesis
what are the skeletal muscle effects of insulin?
increased protein synthesis and increased glycogen synthesis
within adipose tissue, insulin stimulates the processing of circulating lipoproteins to procure free fatty acids, which does what?
facilitating triglyceride synthesis and storage by adipocytes
how does insulin affect triglycerides?
inhibits the hydrolysis of triglycerides
how does insulin affect potassium (K+) levels?
by activating sodium-potassium ATPases, insulin promotes the intracellular movement of potassium (potential for hypokalemia)
ADEs/cautions with insulin and insulin analogs
- hypoglycemia
- weight gain
- local hypertrophy or lipoatrophy of fatty subcutaneous tissue at injection site
drug interaction rating scale
A= no known interaction B= no action needed C= monitor therapy D= consider therapy modification X= avoid combination
insulin risk level X example is
rosiglitazone (thiazolidinedione) the risk of fluid retention, heart failure, and hypoglycemia may be increased with this combination
insulin risk level D examples
may enhance hypoglycemia effect DPP-IV inibitors, GLP-1 agonists, SGLT2 inhibitors, pioglitazone, pramlintide
examples of risk level C drugs with insulin
steroids, beta blockers
reason for caution with beta blockers and insulin
may enhance hypoglycemic effect by altering carbohydrate metabolism and block physiologic response to hypoglycemia
what does the synthetic injectable Amylin analog cause?
delays gastric emptying, decreases postprandial glucagon secretion, and improves satiety
describe the “incretin effect” in terms of glucose changes
oral glucose results in a higher secretion of insulin than occurs when an equal load of glucose is given IV
the “incretin effect” is reduced in ____
type2 diabetes
why does the “incretin effect” occur?
because the gut releases incretin hormones such as glucagon0like peptide (GLP-1) in response to a meal
incretin hormones are responsible for ____ % of postprandial insulin secretion
60-70%
